One hundred and six patients were studied whose cervical smears showed only non-specific inflammatory changes. Screening for genital pathogens yielded only a few positive cases. Histological examination of biopsy specimens taken by colposcopically directed tissue sampling showed cervical intraepithelial neoplasia in 13 of the women (12.3%). Deoxyribonucleic acid (DNA) hybridisation techniques were used to detect human papillomavirus, which was found in 24 patients (22.6%). In a second group of 104 patients with normal cervical cytology tissue biopsy samples were obtained and examined histologically but in no case was cervical intraepithelial neoplasia found. On DNA hybridisation, however, 12 patients (11.5%) were found to be positive for human papillomavirus. In this group finding human papillomavirus DNA was usually associated with a columnar ectopy. An association between human papillomavirus type 16 DNA and both cervical intraepithelial neoplasia and cervical cancer is well established. In this study it was type 16 which occurred most frequently in both groups.